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Bio::Restriction::EnzymeCollection(3pm) User Contributed Perl Documentation Bio::Restriction::EnzymeCollection(3pm)


Bio::Restriction::EnzymeCollection - Set of restriction endonucleases


  use Bio::Restriction::EnzymeCollection;
  # Create a collection with the default enzymes.
  my $default_collection = Bio::Restriction::EnzymeCollection->new();
  # Or create a collection from a REBASE 'withrefm' file obtained from
  # (See Bio::Restriction::IO for more
  # information.)
  my $rebase = Bio::Restriction::IO->new(
      -file   => 'withrefm.610',
      -format => 'withrefm' );
  my $rebase_collection = $rebase->read();
  # Or create an empty collection and set the enzymes later. See
  # 'CUSTOM COLLECTIONS' below for more information.
  my $empty_collection =
    Bio::Restriction::EnzymeCollection->new( -empty => 1 );
  # Get an array of Bio::Restriction::Enzyme objects from the collection.
  my @enzymes = $default_collection->each_enzyme();
  # Get a Bio::Restriction::Enzyme object for a particular enzyme by name.
  my $enz = $default_collection->get_enzyme( 'EcoRI' );
  # Get a Bio::Restriction::EnzymeCollection object containing the enzymes
  # that have the equivalent of 6-bp recognition sequences.
  my $six_cutters = $default_collection->cutters( 6 );
  # Get a Bio::Restriction::EnzymeCollection object containing the enzymes
  # that are rare cutters.
  my $rare_cutters = $default_collection->cutters( -start => 6, -end => 8 );
  # Get a Bio::Restriction::EnzymeCollection object that contains enzymes
  # that generate blunt ends:
  my $blunt_cutters = $default_collection->blunt_enzymes();
  # See 'CUSTOM COLLECTIONS' below for an example of creating a
  # Bio::Restriction::EnzymeCollection object with a specified subset of
  # enzymes using methods provided by the Bio::RestrictionEnzyme class.


Bio::Restriction::EnzymeCollection represents a collection of restriction enzymes.

If you create a new collection directly rather than from a REBASE file using Bio::Restriction::IO, it will be populated by a default set of enzymes with site and cut information only.

Use Bio::Restriction::Analysis to figure out which enzymes are available and where they cut your sequence.


Note that the underlying Bio::Restriction::Enzyme objects have a rich variety of methods that allow more complicated selections than the methods that are defined by Bio::Restriction::EnzymeCollection.

For example, the way to create a custom collection of Type II enzymes is as follows:

  my $complete_collection =
  my $type_ii_collection  =
      Bio::Restriction::EnzymeCollection->new( -empty => 1 );
      grep { $_->type() eq 'II' } $complete_collection->each_enzyme() );


Bio::Restriction::IO - read in enzymes from REBASE files

Bio::Restriction::Analysis - figure out what enzymes cut a sequence

Bio::Restriction::Enzyme - define a single restriction enzyme


Mailing Lists

User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to one of the Bioperl mailing lists. Your participation is much appreciated.                  - General discussion  - About the mailing lists


Please direct usage questions or support issues to the mailing list:

rather than to the module maintainer directly. Many experienced and reponsive experts will be able look at the problem and quickly address it. Please include a thorough description of the problem with code and data examples if at all possible.

Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track the bugs and their resolution. Bug reports can be submitted via the web:


Rob Edwards,


Heikki Lehvaslaiho, heikki-at-bioperl-dot-org


Copyright (c) 2003 Rob Edwards.

Some of this work is Copyright (c) 1997-2002 Steve A. Chervitz. All Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


Methods beginning with a leading underscore are considered private and are intended for internal use by this module. They are not considered part of the public interface and are described here for documentation purposes only.


 Title     : new
 Function  : Initializes the Restriction::EnzymeCollection object
 Returns   : The Restriction::EnzymeCollection object
 Arguments : optional named parameter -empty

Set parameter -empty to true if you do NOT want the collection be populated by the default set of prototype type II enzymes.

Alternatively, pass an array of enzymes to -enzymes parameter.

Manipulate the enzymes within the collection


 Title     : enzyme
 Function  : add/get method for enzymes and enzyme collections
 Returns   : object itself
 Arguments : array of Bio::Restriction::Enzyme and
             Bio::Restriction::EnzymeCollection objects


 Title     : each_enzyme
 Function  : get an array of enzymes
 Returns   : array of Bio::Restriction::Enzyme objects
 Arguments : -


 Title     : get_enzyme
 Function  : Gets a Bio::Restriction::Enzyme object for the enzyme name
 Returns   : A Bio::Restriction::Enzyme object or undef
 Arguments : An enzyme name that is in the collection


 Title     : available_list
 Function  : Gets a list of all the enzymes that we know about
 Returns   : A reference to an array with all the enzyme names
             that we have defined or 0 if none are defined
 Arguments : Nothing
 Comments  : Note, I maintain this for backwards compatibility,
             but I don't like the name as it is very ambiguous


 Title     : longest_cutter
 Function  : Gets the enzyme with the longest recognition site
 Returns   : A Bio::Restriction::Enzyme object
 Arguments : Nothing
 Comments  : Note, this is used by Bio::Restriction::Analysis
             to figure out what to do with circular sequences

Filter enzymes


  Title     : blunt_enzymes
  Function  : Gets a list of all the enzymes that are blunt cutters
  Returns   : A reference to an array with all the enzyme names that
              are blunt cutters or 0 if none are defined
  Arguments : Nothing
  Comments  :

This is an example of the kind of filtering better done by the scripts using the rich collection of methods in Bio::Restriction::Enzyme.


  Title     : cutters
  Function  : Gets a list of all the enzymes that recognize a
              certain size, e.g. 6-cutters
  Usage     : $cutters = $collection->cutters(6);
  Returns   : A reference to an array with all the enzyme names
              that are x cutters or 0 if none are defined
  Arguments : A positive number for the size of cutters to return
              A range: (-start => 6, -end => 8,
                        -inclusive => 1, -exclusive = 0 )

The default for a range is 'inclusive'

2018-10-27 perl v5.26.2